Commercial anionic dyestuffs are generally marketed in the form of finely ground powders that, even after treatment with dedusting oils, have a tendency to dust. The handling of large quantities of such dusty products creates undesirable contamination of the environment and hygienic problems for the personnel handling these products. Dye particles in the atmosphere can also lead to undesirable staining of textile materials, making them less valuable.
Also before use for coloring textiles or paper, the requisite dye powders have to be weighed, wetted out, boiled to bring into solution and filtered to make sure there are no undissolved lumps. This method of preparing the necessary dyestuff solution is therefore costly to the dyer, consuming much labor, time and energy. Also in many cases, the water solubility of the dyestuff is inadequate, especially if the dye solution is allowed to cool prior to its addition to the final dye bath. In the case of continuous operations, where relatively concentrated dyestuff liquors are padded onto fabrics at ambient or only slightly elevated temperatures, the limited solubilities of many dyestuffs in the regular powder form make them unsuitable for use.
To circumvent the handling of powders and obtain the advantages of liquids, a number of manufacturers have resorted to the use of organic solvents. The disadvantages with organic solvents are their added cost, increased load on wastewater treatment facilities during use, and in most cases only limited solubility of the respective anionic dyes.